This has been a great thread. This question comes up again and again, and there are as many varied opinions as to what a good uke is as there are people in the world. I don't really have much to add to the already excellent posts, except that if someone asks you to crank down on them, then do your best to give them what they asked for. These days, I'd rather learn where the flaws in my technique are than have an uke fall down for me, playing on that edge and pushing it a little bit is the key to my personal growth.

In my opinion, one of the reasons this topic comes up from time to time is the fact that we tend to train almost exclusively in paired kata and if you know what the person is going to do next it's easy to get ahead of your partner (both as uke and nage). I tend to look at our paired kata training as the homework that helps us reshape our body and synapses to move in an aikido way, all the while, learning what happens to us and our partners as forces and energy are applied in different directions throughout the techniques. The challenge many of us face is that brain learning is so signicantly different from whole body learning that we struggle to describe our whole body learning process with words. <----See what I mean?

Keep training. If we knew it all already, aikido would be boring. See you on the mat soon, it's always fun to train with you.